Valentine's Day can lead to plenty of broken hearts. But for cardiac wounds that time alone won't heal, science has made some major advances. When it comes to heart attack, for example, a big development is emerging from a tiny source. Stem cells are coming of age.

Stem cells, harvested from a patient's own bone marrow, have been heralded as a potential quick fix for damaged heart tissue. But can these progenitor cells actually work to heal massive muscle damage?

A new review of 33 studies assessed data from more than 1,700 heart attack patients. The review researchers found that those patients treated with stem cells—in addition to the standard care of angioplasty—had stronger tickers for years to come than those who had not gotten stem cell therapy. The review article is published in The Cochrane Library. [David Clifford et al., "Stem Cell Treatment Following a Heart Attack"]

It's too early to say whether those with stem cell treatments will live longer, according to the new analysis. But for affairs of the heart, it's more evidence that good things can come in very small packages.